Never lose sight of the fact that all human felicity lies in man's imagination, and that he cannot think to attain it unless he heeds all his caprices. The most fortunate of persons is he who has the most means to satisfy his vagaries.

In the quote "Never lose sight of the fact that all human felicity lies in man's imagination, and that he cannot think to attain it unless he heeds all his caprices. The most fortunate of persons is he who has the most means to satisfy his vagaries," Marquis de Sade explores the idea that happiness or felicity is rooted in the imagination, and that individuals can only attain true satisfaction by embracing and acting upon their whims or caprices. De Sade suggests that human fulfillment comes not from external possessions or conditions, but from the freedom to explore and satisfy one’s innermost desires, no matter how unconventional or unpredictable they may seem.

De Sade, a controversial French nobleman and writer, is well-known for his works that often explore the themes of freedom, pleasure, and individual desire—often in provocative and challenging ways. His statement reflects his belief in the primacy of personal freedom and self-indulgence in achieving happiness. For him, the imagination is the gateway to exploring one's true desires, and to deny these whims or vagaries would be to deny a path to fulfillment.

The quote also implies that the most fortunate individuals are those who have the resources to pursue their fantasies. In de Sade’s view, the ability to satisfy one's desires is a form of freedom, and the wealthier someone is, the more opportunities they have to indulge their impulses. This perspective is aligned with his broader philosophy that individual desire should not be suppressed but embraced, as long as it is pursued with freedom and without restrictions imposed by society or morality.

Ultimately, de Sade’s quote underscores his radical view that imagination and freedom are central to human happiness. The ability to live in accordance with one's whims—to explore and act on one's innermost desires—defines true felicity, and those who are fortunate enough to have the means to do so are in a privileged position. This perspective challenges conventional views of morality and happiness, emphasizing individual freedom as the key to personal fulfillment.